This is the first installment in a discussion of dietary fats, with respect to prostate cancer. Consideration is also given to cardiovascular health.

The primary focus is on the cancer paradox: that the ratio of oleic acid to stearic acid increases as cancer progresses. Does it make sense to limit ‘beneficial’ oleic acid intake? And might ‘harmful’ stearic acid be beneficial in this instance?

A. Summary.

Olive oil is considered to be a ‘healthy’ fat, & this is largely attributed to oleic acid.

Stearic acid – from the Greek word for tallow – is a saturated animal fat, & is therefore considered to be ‘unhealthy’.

The supposed association of stearic acid → cholesterol → cardiovascular disease does not exist. In terms of cholesterol, stearic acid is neutral.

While corn oil can accelerate PCa progression in animal studies, saturated fat is neutral. Olive oil has not been used in such a study, but is unlikely to stimulate growth, IMO.

Stearic acid in circulation has been associated with reduced PCa risk in two large studies.

The body converts excess stearic acid to oleic acid.

In many cancers, the ratio of oleic:stearic acid increases with the severity of the cancer. This seems to indicate that oleic acid is not a useful addition to the diet when one has PCa.

On the other hand, an oleic-dominant ratio is seemingly an artifact of the cancer & probably unrelated to diet. This dominance is seen, not only in cancer cells, but also in red blood cells.

Men in many of the Mediterranean countries have very low rates of PCa mortality, but this may have more to do with the high fat nature of the various diets (up to 40%) than with the type of fat. However, diets of the region tend to use olive oil primarily.

Dr. Charles Myers strongly recommends that men with PCa embrace the Mediterranean diet. He emphasizes that it is not low fat. He says that patients on a low fat (i.e. high carbohydrate) diet do not do well. The Med diet reduces cardiovascular risk factors that many of his PCa patients present with. [Aa]

B. Introduction.

B1. A general note on fatty acids.

Fatty acids consist of carbon chains of various lengths, where each carbon may or may not be hydrogenated. If every carbon has hydrogen connections, the fat is classed as 'saturated'. Unsaturated fats are said to have 'double bonds' in the locations not hydrogenated. Monounsaturated fats have only one double bond. Polyunsaturated fats have more than one – (a long name conveying very little).

Sweeping generalizations are made about saturated, monounsaturated & polyunsaturated fatty acids, but each fat is unique & best described by the length of the carbon chain, & the specific locations of the double bonds. The smallest variation can have profound effects in the body.

Of some use is the position of the last double bond in the carbon chain - e.g. ‘omega-3’ means it is located 3 carbons from the end. The body creates longer-chain fats, as needed, from those on hand. The carbon extension happens at the front & while other double bonds may be added, they do not affect the omega designation.

B2. Oleic & Stearic acids.

Oleic & stearic acids have similar structures. They both have 18 carbons. Stearic is saturated, so is rigid. Oleic is monounsaturated & is an omega-9, so it bends exactly in the middle. That’s the only difference. Stearic acid is a fat found in red meat, whereas oleic acid is the major fatty acid in olive oil. Stearic acid is solid at room temperature - it is used in candle production - while oleic acid is liquid. Stearic acid has been vilified for most of my life, while oleic acid (via olive oil) is currently extolled for its health-giving properties.

I continue to be amazed that two fats as chemically close as stearic & oleic acids – the only difference being a single double bond - could have such black & white public images. In fact, stearic acid doesn’t deserve its negative press..

C. Oleic acid.

Oleic acid is found in many oils & and animal fats. It is over 70% of olive oil, but also almost 50% of lard. So what makes olive oil so special?

C1. Olive Oil.

The major dietary fat in the Mediterranian region is olive oil. The trees do well there. But, of major significance, is that the much-lauded Mediterranean diet is 40% fat. One can reduce the fat somewhat, or a lot; but why? Would people in the region be healthier if they cut down on olive oil?

The U.S. food pyramid has carbohydrate (bread, cereal, rice & pasta) at its base & fats at the apex. The Med pyramid has olive oil, vegetables, fruits & some grains at its base. Quite different. In other words, an American would have to do a lot more than switch from corn oil to olive oil to reap the benefits of the Med diet.

Most of the olive oil on the American market is imported from European Union countries. A shameful fact is that the EU has not been able to clean up the olive oil market. Adulteration is lucrative & organized crime is entrenched in the industry.

In 2007, Tom Mueller wrote an influential piece in the New Yorker [C1a]. It begins:

"On August 10, 1991, a rusty tanker called the Mazal II docked at the industrial port of Ordu, in Turkey, and pumped twenty-two hundred tons of hazelnut oil into its hold. The ship then embarked on a meandering voyage through the Mediterranean and the North Sea. By September 21st, when the Mazal II reached Barletta, a port in Puglia, in southern Italy, its cargo had become, on the ship’s official documents, Greek olive oil. It slipped through customs, possibly with the connivance of an official, was piped into tanker trucks, and was delivered to the refinery of Riolio, an Italian olive-oil producer based in Barletta. There it was sold—in some instances blended with real olive oil—to Riolio customers."

It is a disheartening story.

Wikipedia [C1b]: "With Italian extra-virgin olive oil in high demand with concomitant high prices, adulterated olive oil has become the biggest source of agricultural fraud problems in the European Union. While less than 10% of world olive oil production meets the criteria for labeling as extra-virgin, it has been estimated that up to 50% of retail oil is labeled "extra-virgin". Some oil labeled "extra-virgin" is diluted with cheaper olive oils or other vegetable oils. In some cases, lampante, or "lamp oil," which is made from spoiled olives fallen from trees, is used, even though it can't legally be sold as food. One fraud ring is accused of coloring low-grade soy oil and canola oil with industrial chlorophyll, and flavoring it with beta-carotene."

In 2012, Mueller followed up with a full-length book: "“Extra Virginity: The Sublime and Scandalous World of Olive Oil". [C1c]

After reading the New Yorker piece, I decided that domestic oil might be a safer bet. I settled on oil from the Sciabica Family. [C1d] One orders according to the season, so that it is freshly pressed when received.

A frustrating thing about imported extra virgin olive oil is that the production year is rarely on the bottle label. And when it is, the oil is often older than it should be. Unlike fine wine, it does not improve with age.

{Why is it that chefs often say: “Don’t use your best olive oil for this …”? That’s like saying it’s sometimes OK to use margarine instead of butter if no-one will notice. Second-pressing oils are second rate. Most cooking does not take the oil close to the smoke point, & some of the beneficial polyphenols will survive undamaged.}

C2. Olive Oil Polyphenols.

Some like to attribute the benefits of olive oil to its polyphenols. Perhaps it’s easy for those who use only extra-virgin olive oil [EVOO], to forget that most olive oil used for cooking in the Mediterranean region is not EVOO quality & not a good source of polyphenols.

In the context of a 40% fat Mediterranean diet with EVOO, phenolic intake might be significant.

Hydroxytyrosol is the main polyphenol, but it should be noted that levels are much higher in the olive leaf. Olea25 is an olive leaf extract that is standardized to 25% Hydroxytyrosol. [C2a]

A 2016 Italian cell study [C2b] reported:

“The proliferation of all the cell lines was inhibited but at different levels: the prostate cancer cells were more resistant to the growth inhibition with respect to breast and colon cancer cells.”

Oleuropein is another compound that has been tested on PCa cells (2012 – Italy) [C2c]:

“Exposing cell cultures to oleuropein induces an antioxidant effect on BPH-1 cells and a pro-oxidant effect on cancer cells. Our results confirm the beneficial properties of olive oil and oleuropein”

Again, the leaf is perhaps a better source.

C3. Circualting Oleic acid in Human PCa studies.

[C3a] (2013 – Australia)

“We performed a case-cohort analysis within the Melbourne Collaborative Cohort Study using a random sample of 1,717 men and 464 prostate cancer cases to investigate associations between fatty acids assessed in plasma phospholipids (PPLs) or diet”

Most foodies seem to agree that beef tallow (19% stearic acid) makes the tastiest French fries. Which perhaps explains why fast food chains only began to phase it out from 1990 – 35 years after Americans were advised to avoid animal fats.

A local supermarket caters to our old mountain families & new retirees from afar. They sell obscure pig parts along with sushi-grade tuna. You can find a tub of lard if you look hard - but no beef fat. It seems to me that it has been eradicated from the marketplace. Indicative of the horror with which it is now viewed.

There was an alternative theory. In the U.K., John Yudkin [D1b] blamed sugar.

{Sugar consumption in the U.S was ~6 lbs/year per person in 1820 & rose steadily over the next hundred years to 80 lbs in 1920. It began to rise again in 1960 & hit ~105 lbs in 2000. [D1c]}

Keys' view took hold in the U.S. & it was almost impossible for researchers to get funding if they held contrarian views.

One of those in the Keys camp was David Mark Hegsted [D1d]. He was at the Harvard School of Public Health from 1942 to 1978. His work on saturated fat & cholesterol was influential.

"In 1967, Hegsted and two other Harvard scientists took, without attribution, $6,500 (nearly $50,000 in 2016 equivalent dollars) from the Sugar Association to produce a review of industry-selected research. The resulting paper in the New England Journal of Medicine "minimized the link between sugar and heart health and cast aspersions on the role of saturated fat [as primarily causing heart problems]". The paper helped to shape nutrition guidance for decades away from even considering the dangers to the heart of sugar and its role in obesity in the human diet."

Also involved in the sugar study was Fredrick John Stare [D1e]. "In 1942, Stare founded the Department of Nutrition at Harvard School of Public Health which he led as a professor of nutrition until his retirement in 1976." "Stare {once stated} that Coca-Cola was "a healthy between-meals snack". In an interview Stare claimed that eating even great amounts of sugar would not cause health problems."

Take that John Yudkin!

I see that it is now possible to buy tallow from grass-fed beef online:

Rodent studies consistently reported the benefits of a low fat diet in PCa until Steve Freedland realized that the standard chow contained corn oil. Corn oil has linoleic acid, a pro-inflammatory omega-6 fatty acid. He repeated one experiment substituting saturated fat for the corn oil. There was no benefit to the low fat diet. What the older studies were really saying was stay away from corn oil.

"These results suggest type of fat may affect PCa growth as much as, or perhaps more than, amount of fat." [D2a]

More tellingly, it suggests that stearic acid does not affect PCa progression.

D3. Stearic acid is cholesterol-neutral.

Here is a paper from 1999 [D3a]:

"The reason dietary stearic acid is considered benign is based on its failure to elevate plasma cholesterol concentrations. Stearic acid is well absorbed by the gut and is transported in chylomicrons and remnant particles before being picked up by the liver. Once there, an interesting paradox occurs in that excess stearic acid is simply converted to the 18-carbon monounsaturated oleic acid via a desaturase enzyme in the liver (4) and then recirculates in lipoprotein complexes as oleic acid, which is not hypercholesterolemic."

A 12% risk reduction for being in the highest quintile versus the lowest.

[D4b] (2008 – European – Epic study)

“This was a nested case-control analysis of 962 men with a diagnosis of prostate cancer after a median follow-up time of 4.2 y and 1061 matched controls who were taking part in the European Prospective Investigation into Cancer and Nutrition.”

Another large study.

“We found an inverse association between stearic acid and the risk of total, localized, and low-grade prostate cancer; men in the highest quintile of stearic acid had a relative risk of 0.77 …”

“Dutch men … had the highest proportion of stearic acid”. {“Men from Italy had the highest proportion of oleic acid”}.

This suggests that diet had an important role in these findings. It appears that fasting levels were not measured.

The finding does not mean that Dutch men have less PCa than Italians, say, – quite the reverse – but that those with lower levels of stearic acid in any national group have a higher risk of PCa. In fact, lower levels may be due to the cancer itself.

"The red cell membrane stearic acid to oleic acid ratio was analysed in 34 men with histologically proven carcinoma of the prostate and distant metastases. This ratio was expressed as the saturation index (SI). A mean SI of 0.97 was found in control patients without evidence of any malignancy whereas all patients with advanced prostatic cancer showed a reduced stearic to oleic acid ratio (mean SI 0.466). Untreated patients had a significantly lower SI (mean 0.36) than those who had responded to hormonal therapy (mean 0.547 ...). A drop in SI correlated well with more advanced disease as judged by radiological findings and serum PSA. It is suggested that red cell membrane SI correlates well with radiological and biochemical markers of advanced prostatic carcinoma and may be used as a marker to assess progress and response to treatment."

[Ec] (2004 - U.S.)

"Analyses of RBCs membrane fatty acids were performed for 255 patients with different types of cancer (breast, prostate, liver, pancreas, colon, and lung), 2,800 non-cancer patients and 34 healthy volunteers. Our research study demonstrated a lower level of stearic acid and an increased content of oleic acid in RBC of cancer patients in comparison with control and non-cancer patients."

[Ed] (2002 - Greece)

"The subjects were 71 male patients from the island of Crete. Half the patients (n=35) had been diagnosed with benign hyperplasia of the prostate, half with prostatic malignancy (n=36)."

"Alteration of lipid metabolism associated with malignant disease is well-documented and some studies have suggested a reduced stearic to oleic acid ratio occurs in erythrocytes {red blood cells} in cancer patients. In this study, the fatty acid composition was measured in platelets, which are capable of lipid synthesis and have a much shorter lifespan."